1. No opinion
2. I really liked Slaying, but now that I think about it I don't think I've really skilled it since worms where gone. I'm not sure why you think the other songs are nonviable, I use Trees, Este, Freedom, and Smithing.
3. Very poorly, so I can't give good feedback on how the farey past 600'
4. Yes I smith. I think the power curve is U-shaped, with amazing utility for a few pts, then quickly diminishing utility until I can get it to 30ish
5. I use Warhammers (heh), Throwing Axes (until I need the space), rarely a great axe.
6. Robes only If I can smith an amazing artifact, or the artifact one drops. Otherwise leather.
7. Focus I've goofed off with and enjoyed, but resulted in weak gimmicks.